Various middle distillate fuel oils tend, with time, to deteriorate. Normally, distillate fuel oils are stable during standing. However, some distillate fuel oils that contain abnormally high levels of organic acid and sulfur containing species can be quite unstable and may deteriorate. This deterioration usually results in the formation of sediment, sludge, or gum and objectionable color deterioration during transportation and storage. This fuel oil deterioration is caused, in part, by the presence of oxygen in the storage tank containing the fuel oil. Resulting oxidation of the fuel oil manifests itself in the appearance of darker colors, gum and the like. Sediment formation may cause clogging of fuel system equipment such as filters, screens, nozzles, burners and other associated equipment. This problem may be further aggravated when cracked material is blended with distillate fuels. Discoloration of distillate fuel oils is objectionable for various reasons, including customers' preference for light colored fuel oils because discolorization may indicate that deterioration has occurred.